Thermally actuated friction clutch



April 4, 195.0 s. A. KANE 2,502,461

THERMALLY vAc'1'um'12fb,-FRICTION CLUTCH Filed Dec. 22, 1948 INVENToR.

Soul Allan Kane Attorney Patented Apr. 4, 1950 UNXTED STATES PATENT OFFICE 10 Claims.

amended April 30, 1928; 370 0. G. 757) This invention relates to a friction clutch, and more particularly to a thermally actuated clutch for frictionally connecting driving and driven members.

In high-torque power transmission devices, such as employed for example in ship propulsion machinery, it often becomes desirable to disconnect the driven device, such as the propeller, from the driving machinery particularly in the event of damage to either, not only to make repairs but to prevent the driven portion, such as the propeller, from turning the damaged unit and exerting a drag upon the Vehicle; and in the event the driven parts require repair, the driving machinery can still continue tooperate to run its auxiliary apparatus.

The present type of clutching units are not suitable for this form of power transmission: a plate-type friction clutch would bev unsatisfactory for the reason that the overall size required to transmit the high torque would be excessive relative to the space and weight factors involved; a jaw-type clutch while suitable for this type of transmission is undesirable for clutching or declutching cannot be accomplished without Stopping the propulsion unit, an unsatisfactory procedure as the propulsion unit often drives auxiliary apparatus; and a helical spring clutch being unilateral in operation cannot be employed with reversible driving units.

There is, therefore, a need for a clutch having suitable space and weight proportions that may be actuated irrespective of the speed or direction of rotation of the propulsion or the driven unit and one in which the torque-transmission capacity can be varied without substantially increasing its overall length. 4

An object of the invention therefore is to provide a clutching mechanism that will meet the aforementioned needs. p

An additional object is the provision of a clutch l, that will be responsive to predetermined temperature ranges of a circulating or ambient fluid to connect or interrupt the transmission of power between driving and driven elements. v

A-still further object of the present invention is to provide a clutch mechanism that willfunction with a change in temperature to interrupt the flow of power between driving and driven' parts.

A still further additional object is to provide a clutch with a thermally responsive element such as an expansible-contractible element. Y

Other attendant advantages -of this inventionv will be readily appreciated as the same becomesl better understood by reference to the following detailed description when considered in connection with the accompanying drawings in which like reference numerals refer to like parts throughout the figures and wherein:

Figure l is a longitudinal cross section of one embodiment of the invention taken on line I-I of Figure 2;

Figure 2 is a cross sectional view taken on line 2-2 of Figure l Figure 3 is a longitudinal cross section of a modification taken on line 3-3 of Figure 4;

Figure 4 is a cross sectional view taken on line 4-4 of Figure 3; and

Figure 5 is a perspective view of an end portion of an element of Figure 3.

Referring to the drawings, a propeller shaftV Il connected to propulsion machinery, not shown, is provided with a bore I2 and a plurality of keyways or fiuid channels I3 extending lengthwise of the shaft and spaced circumferentially about the shaft axis. The bore I2 is connected by a plurality of radial passages Ill to the channels I3. A sleeve I5 fits over the shaft II and is provided with a series of parallel keys I6 extending along its length. The keys II-are received within the fluid channels I3, as more clearly shown in Figure 2, and can move into and out of these channels in a radial direction for a purpose to appear. The bore I2 is closed by a washer I2' and a threaded member I3' which is provided with a flange Il for closing the fluid channels I 3.

The material for sleeve I5 is selected for its high coefficient of expansion and such material can be any one of the copper base alloys, such as bronze. The reason for the requirement for such metal will become apparent as the description proceeds.

Fixed to the external periphery of the sleeve I5, by riveting or other suitable means, are a number of friction shoes Il, Il which are adapted to engage the internal periphery of a tubular casing I8 attached to a driven shaft I9 by any suitable means, such as the bolt 2li and key 2 I.

To operate the clutch, suitably heated fluid, such as water or steam, is introduced into the bore` I2 from whence it'flows through the radial passages Ill into the channels I3 to contact the keys I6. The` keys I6 will be heated and by conduction will raise the temperature of the sleeve I5 causing it to enlarge bodily toward the inner surface of the tubular casing I8. This expansion of the sleeve I5 will move the friction shoes Il, I'l' against the inner surface of the tubular casing I8 with sumcient force to grip and turn it in unison with the driving shaft I I.

In the event steam is employed as the heating fluid for raising the temperature of the sleeve I5, the threaded member I3 is provided with a drain hole 22 for the drainage of any condensed steam. The tubular casing. I8.is furnishedwth one or more drain. holes 23 toallow for the escape of any fluid which if permitted to accumulate in the tubular casing may eiect the efficiency of the friction shoes I'I, II.

To disconnect the driven shaft I9, any-'suitable coolant, such as sea water, is fed into..the..bor.e. I2 and reaches the channels I3, in the manner explained, to cool the keys IEE. 'Dhisii'rturnwill decrease the temperature of the sleeve I and To establishcommunication between the space separating the Walls of the bore and tube, the outer chamber 35, and the channels 41, the shaft is provided with one or more inlet passageways 53 and one or more outlet passageways 54. The end of the bore 3| is closed by a gasket 555 anda cap. 5.5. fastened to the end of the shaft 3i) bytb'olts 5.1i.

Although the incoming fluid is introduced through pipe 42 and drained by pipe 4I, resulting in the fluid flowing in the direction indicated by the arrowss of Figure 3, the position of pipes 4I and llimay. he reversed and the fluid introduced cause it to shrink, withdrawing the frictions'hoesf I1, I'I from engagement with theftubular. casing I8 and freeing the driven shaft I9;

As the heating and cooling fluids need be fed intothe borel I2. witha. minimum.. of. pressure, fluid. sealing dev-ices which would. normally. be employed between. the .keys 1.61 and'. the. channels I.3are.omitted for, the reason that. theelea'kage of fluid', if any,.is-.of. a. negligible.. amount anddoes not affectthe operation or. efficiency of thejinit.

As, the operation. of, theclutch` is. dependent upon the expansion and the contraction of, the sleeve I .5, suchoperationmay be. made. automatic by omitting the heating and cooling, fluids.v and relying. upon the temperature. of the. ambient.. atmosphere.. surroundingfthe clutch.. to. cause the sleeve Y I5t to. enlarger shrink. similarly as under the influence of the iluids in thebore. i2..

In.. thel embodiment. oi. Figure. 31provision. is A made for positively circulating-,the fluid` through the,4 clutch. Thus,` the. propulsion shaft 3&1 provided .withanenlarged axialborej I within which is located atubc or. sleeve 32'. Thetube 32jis concentricalli,7 positioned withinthebore jby. a pair of. spacer .plugs.33`,' .3.4L

The.. plugs.. 33,', 34' are made. Water-tight with boththebore. 3i and. the. tube. 32.thereby forming concentric.. passages.. 3.6, 3I through` which huid can-flow.. The. endsof.. the tub.e.32,' beyond'the spacers 33.34`,are providedlwith. a number of axially. extending. slots 35, 35", as` more clearly shoWnin. FigureI 5; for apurposetc appear..

About. the. shaft 3.9' is a stationary sleeve133 provided with. annular passages 39; 40. The annular passage4 4XL is. connectedto la drain pipe 4I and theI remaining annular` passage 39 .is filled withjluid. from a feed pipe` 42'; provided" with a reducing valve 43;. The feed pipe 42 is..connected to aconventionaltwofwayvalve 44;

Leadingint'o. the Valve 44 are pipes" and46 which. are connected to any suitableY source` of hot and cold fluids. Thus, pipe 45' maybe connected to .any nearby steam or. hotl water lineand the pipe ll'rnay be-supplied with cold-sea water.

Asi the operationv of" the clutch 'isdependent upon temperature changes rather-than pressure', thereducing-valveAt" in. pipe 42' i'sl used. However', the' valve 43' may be'ornitted' andthe pipes 45, 46 connected. directlyA to'.lowepressurelines carrying-fthe iiuidsfat the desired temperatures.

Ther end; of'V the: drivingV shaft 3i! isconstructed simiiarfto that; ofiE-igures.. 1.andi2. .Itis, thus, provided.with fluidichannels-i 41.. slidalolyreeeiying.. keys.; 48.? attached, to; thel expansibleecontracte ible.- sleevel 49, to,- which'l are fastened; friction shoes t-, d. which..are.adapted to. .engagez a tubue lar.-V casingi 5I attached. tothe. drivengshaft 5.2. Thesepartsare.similar tov and function.. the same asthose describedinFigures. 1 and'2.

into the lannular passage 40 and drained through the-annular'passagefi.

As. shown in Figure 3, the valve 44 is in a p0- siti'on to admit heated fluid from pipe 45 into feed pipe 42 fromwhence it flows into the chamberf?. for' distribution through the inlet passages 53 to the channels 41 for heating the sleeve 49 as in. Figure. l.. The fluidirom thechannels-Il leave'. by way. oil the: outlet passages- 5d.. into,h the space.Y of, thebore 3l formedbetween'the; spacer 33 and the cap 56.

Thenuid. then. passes through.. the, slots.y 35 into the.. tube.. 36; for. delivery,r through its? other end. slots to the bore.space,. between. the end of.. the borel and the. spacer. 34,.. from. whence it vis. drained ol. by pipe .4..I k

To interrupt.. the.. vilo-W.. of... power. between. the shafts 3H and4 52, the..valve. 44 is.. operated to place. the cold.'.fluid pipelliv in communication with.. pipe. 42; as;y a.. result of. which.. cold iluid Awill take.. the lsame.. path .as already. described. for the heated huid". z H

`The sleeve 49 will function. sriiilarlyl to,Y the sleeve. I 5. of. Figure.: 1.. to... advance .or to.. retract7 the friction.. shoes. 5i) .from the tubular. casing .5' I

The vtorque-transmission` capacityr or .the-clutch may, be. varied 'tofmeet` differentreqnirements by varying. the length. or. either eXpans-iblefeontractible.sleev.e,-I5..or 43.'. Thus, forexampleinFigure 3. to'. increasethe ability. of the clutch to transmit' power., the sleeve.. 49 can be extended; axially, and conversely, it mayT be .shortened when power requirements .so permit...

It should., be understood, of. course, that although. the` foregoing.. disclosure relates to pre.- ferredY embodiments. of. the. invention, numerous modications or alterations may. be made vtherein withoutdeparting from. the` spirit. andthe scope o the invention. as. set.- forth. in the appended claims.

Theinventiondescribed herein.- may be manufactured and.used. by or for the Government. ci the United.. States of. America. for governmental purposes without the payment of. any. royalties thereon .ortherein;

Having thusidescrihed the invention, what is claimed is:

1.In.. a. power.v transmitting; mechanism, the combinationbf. adrivingshaftl having an end portion.. and an.. axial .bore therethrough. for. the reception of. a fluida;` drivenshaft.inaxialalignment therewith, a. tubular; casing. secured tov said drivenshaft, and..concer;trically4 surrounding, said driving shat...end1portion,. .aplurality oi. channels extending longitudinally;v ori and spaced'. `on said end portion, radial. passagesconnecting. said-.bore with'said' channels for distributing the iluid within .said .boregtog Saidhanneiaa. thernfially.` expansiblef-contractiblecylindrical sleeve;abcut said .end portion, a plurality.of..leys..on theinnerperiphery of... said.. sleeve. dependingginto said.- channels; for

. contactY with. the?.` fluid.ther.ein'. whereby..A the di cured to said driven shaft and positioned about driving shaft, a plurality of channels on said driving shaft, passages connecting said bore with said channels for distributing the fluid within said bore to said channels, a thermally expansible-contractible sleeve about said driving shaft, projections on said sleeve fitting into said channels for contact with the fluid therein, friction shoes on said expansible-contractible sleeve whereby expansion of the same will move said friction shoes against said tubular casing.

3. In a power transmitting mechanism, the combination of a driving shaft, a driven shaft, a sleeve secured to said driven shaft, grooves on said driving shaft, a thermally expansible-contractible means about said driving shaft, projections on said means engaging said grooves whereby expansion of said means will drivingly engage said sleeve.

4. In a power transmitting mechanism, the combination of a driving means, a driven means, and a thermally expansible-contractible means between said first pair of means, said expansiblecontractible means being a sleeve about and driven by said driving means, said driven means being adapted for driving engagement by said expansible-contractible means upon thermal expansion of the same.

5. In a power transmission device, thecombination of a driving shaft having an end portion and an axial bore therethrough, removable means on the end of said driving shaft closing said axial bore, a tube extending within and substantially the length of said axial bore, annular spacers in said axial bore at predetermined distances from the ends thereof supporting said tube in concentric relationship with said axial bore, the ends of said tube beyond the annular spacers being provided with slots, an annular stationary sleeve on said driving shaft having a first and a second annular groove, means connected to said first annular groove for alternately supplying the same with fluids of relatively higher and lower predetermined temperatures, an inlet passage in said driving shaft connecting said first annular groove with said bore intermediate the annular spacers therein, an outlet passage in said driving shaft connecting said second annular groove with said bore intermediate an end thereof and an annular spacer adjacent thereto, means on said annular stationary sleeve for draining the fluid from said second annular groove, a plurality of longitudinally extending channels circumferentially spaced on said end portion, inlet radial passageways connecting said channels with said bore intermediate said annular spacers for distributing the lfluid within said bore and between said annular spacers to said channels, outlet radial passageways connecting said channels with said bore intermediate said removable means and an annular spacer ad jacent thereto whereby the fluid from said channels flows into said tube, a thermally expansiblecontractible sleeve on said end portion, a plurality of keys on the inner periphery of said sleeve Jai depending into said channels for contact with the fluid owing therein whereby the diameter of said sleeve will vary with the temperature of the fluid, a plurality of circumferentially-extending friction shoes attached to the outer periphery of said sleeve for movementy therewith, a driven shaft in axial alignment with said driving shaft, a tubular casing secured to said drivenshaft and concentrically positioned about said sleeve, whereby expansion of said sleeve will move said friction shoes into driving engagement with said tubular casing.

6. In a power transmission device, the combination of a driving shaft having a plurality of channels extending longitudinally and spaced circumferentially thereof, means circulating fluid through said channels, a thermally expansiblecontractible sleeveabout said driving shaft, keys on said sleeve depending into said channels for contact with the fluid flowing therein whereby the diameter of said sleeve will vary with the temperature of the fluid, friction shoes attached to said sleeve for movement therewith, a driven shaft, a tubular casing secured to said driven shaft and surrounding said sleeve, whereby expansion of said expansible-contractible sleeve will move said friction shoes into driving engagement with said tubular casing.

7. In a power transmission mechanism, the combination of a driving shaft having a bore, means within said bore dividing the same into concentric fluid chambers, longitudinally-extending channels circumferentially-spaced on said driving shaft, means connecting opposite ends of said channels with said fluid chambers, respectively, for circulating fluid through said channels, a thermally expansible-contractible cylindrical ksleeve about said driving shaft, keys on said sleeve internally thereof and depending into said channels for contact with the fluid flowing therein whereby the diameter of said sleeve will vary with the temperature of the fluid, friction shoes attached to said sleeve for movement therewith, a driven shaft in axial alignment with said driving shaft, a tubular casing secured to said driven shaft and concentrically surrounding said sleeve, whereby upon expansion of said sleeve said friction shoes will drivingly engage said tubular casing.

8. In a power transmission mechanism, the combination of a driving shaft, a thermally expansible-contractible means drivingly connected to said driving shaft, said expansible-contractible means being a sleeve about said driving shaft, means circulating fluid in contact with said expansible-contractible means whereby the same Will vary bodily with the temperature of the fluid, and a driven means adapted to be drivingly engaged by said expansible-contractible means.

9. In a power transmission mechanism, the combination of a driving shaft, a thermally expansible-contractible means drivingly connected to said driving shaft, a plurality of keys on the inner periphery of said expansible-contractible means, a plurality of grooves in said driving shaft for receiving said keys, means circulating fluid pansiblemontractiblef sleeveA aboutie saida" driving shaftwithprojctonstengagingfsadgrooves, fric:-y tin i shoes? attached-:t0 sa'id" sleeveflffor muvement therewith,` a tubularcasing'secured tosaa'd driven shaft and?sum'oundngf:saId-sleeve,` whereby eX- ansn of saidexpansible#contractiblsleve will Inov saiwiction 'ShoesV intodiivihg Iengagement with said=tub1r casing;

SAUL.' vAT .LArzr KANE.

8 REEEEENGESA- The following references aire of recordI in the fue of* this patent:

UNITED' 4STA'ES PATENTS Nmber Name' Date 2,087,488 Stanley;V July 20.; 193'? 2,093,281 Kreuser n Sept. 14,;193'7 2,320,900 Walz'-; July 1, 1943 

